Storage containers for radioactive material are common place and widely used to transport spent fuel pins from nuclear powder reactors and to transport radioisotopes for use in medicine and industry. Containers suitable for transporting radioactive material must be designed to withstand severe impact yet retain their integrity to prevent unacceptable nuclear contamination if the container is involved in an accident.
Such transportation type containers are generally heavy and bulky and are inapplicable for use in the laboratory where small amounts of radioactive material must be stored, yet be readily available for inventory or use. Such a laboratory storage container should provide adequate shielding to prevent workers from being exposed to harmful radiation and also to prevent the escape of radioactive material. On the otherhand, because the radioactive material is often used for experimental purposes, the container should be designed for ready access to the material not only for day-to-day experimental use but also for inventory control. Because plutonium as well as enriched uranium is often used in experimental facilities, a criticality problem exists which must be taken into account in the container design to prevent container stacking which may result in a critical mass being formed. Accordingly, containers suitable for laboratory use which meet all the requirements described above would generally not be suitable for transporting radioactive material by common carrier.
Representative literature pertinent to transportation containers include the Allen U.S. Pat. No. 3,113,215 issued Dec. 3, 1963 for Cask Construction For Radioactive Material. This patent discloses a cask construction for radioactive material including a screwed down top plate with a gasket seal. The Bonilla et al. U.S. Pat. No. 3,229,096 issued Jan. 11, 1966 for Shipping Container For Spent Nuclear Reactor Fuel Elements discloses a container including a screwed down cover with a vent and with a ring handle.
The Lecuyer U.S. Pat. No. 3,560,749 issued Feb. 2, 1971 for Container Means For a Radioactive Element discloses a container having interchangeable storage bodies formed of a radioactive shielding material.
The Peterson et al. U.S. Pat. No. 3,731,101 issued May. 1, 1973 for Shipping Container For Radioactive Material discloses a container with a gasket seal at the top of the container and screws for maintaining the top in place.
The Backus U.S. Pat. No. 3,770,964 issued Nov. 6, 1973 for Shipping Container for Radioactive Material discloses a cask with a screw down top plate and annular gasket sealing same.
The Czaplinski et al. U.S. Pat. No. 4,084,097 issued Apr. 11, 1978 for Shielded Container discloses a container having a handle pivoted thereto which includes means for measuring the radioactivity of the solution stored therewithin.
Other patents generally pertinent to the subject matter include the Anderson et al. U.S. Pat. No. 3,569,714 issued Mar. 9, 1971 for Protected Radioisotopic Heat Source which discloses a protected radioisotopic heat source including a cover fitted on a plate on which the source rests and the Johnson U.S. Pat. No. 3,953,288 issued Apr. 27, 1976 for Gas Venting discloses containers housing radioactive material which utilize the passageways between interbonded impervious laminae.